I-75/University Drive Diverging Diamond Interchange (DDI)

A first-of-its-kind in Michigan, this innovative interchange does double duty by solving a complex infrastructure problem while positioning the City of Auburn Hills as a high-tech leader.

Overview
A revolutionary solution keeps things moving forward in Auburn Hills.

Home to Fiat Chrysler North America Headquarters and Oakland University, the City of Auburn Hills is known for its booming business climate. But aging infrastructure at the gateway to its university and business district told another story. A critically deteriorating bridge and roadway at the I-75/University Drive interchange backed traffic up for miles. Commuting was a nightmare. People and businesses were frustrated. Not to mention the safety and environmental concerns stemming from all the congestion.

The interchange had long been a problem. Back in the 90s, the Michigan Department of Transportation (MDOT) had a plan to fix it using traditional cloverleaf ramps and auxiliary lanes along I-75. Work started. A solution was on the horizon. But then in 2005, the project was shelved indefinitely due to funding priorities, leaving a partial solution that made the situation worse.

Daily calls continued to come in from disgruntled motorists and business leaders. City officials knew they were in danger of losing business or missing out on new opportunities due to the state of the aging infrastructure. They needed a creative and cost-effective solution that could help generate new sources of funding for the project. So in 2008, city leaders tapped long-time partner OHM Advisors to lead a national innovative concept study of potential interchange configurations. Our response: a novel diverging diamond interchange that could alleviate the traffic problems and set the tone for the city’s vital business and higher education resources.

 

Thinking Differently

Introducing Michigan to the Diverging Diamond Interchange.

At the time of our concept study, the first DDI had yet to be fully built and was virtually unheard of in the U.S. However, by carefully analyzing the DDI then under construction in Missouri and performing extensive traffic modeling, our team validated the feasibility of the innovative solution. We proved that a DDI could safely move the highest volume of traffic and resolve the congestion problem in Auburn Hills. We showed how a smaller footprint and tighter ramp configurations could save more than $10 million while eliminating 20 right-of-way parcels, two acres of wetland impacts, 3,000 feet of sound wall, and four bridges compared to MDOT’s previous design. Our efforts garnered support from both city and MDOT officials for the novel concept.

Eliminating left turn conflicts – the sweet spot for DDI.

We knew the DDI would be the ideal solution for the University Drive/I-75 interchange because it eliminates left turn conflicts, which were causing major bottlenecks for motorists leaving the city via I-75. The concept works by using two signalized intersections on either side of the freeway bridge to cross drivers to the left, or opposite, side of the road through the interchange, then back to the right side. This allows for unimpeded left-turning traffic while eliminating loop ramps. At the same time, the DDI eliminated the need for Chrysler traffic to navigate through the University Drive interchange. Those motorists now enjoy direct access to I-75, which means fewer vehicles passing through the signals at the interchange.

Building a coalition of support through a unique funding approach.

To secure funding, the city applied for five federal TIGER grants between 2009 and 2013 under OHM Advisors’ leadership. All five grant submissions made the final cut, but none received funding. Still, the process laid the groundwork for support from various stakeholders, including state legislators and federal representatives. In an untraditional move, the city approached the university and current and potential local businesses. Ultimately, Oakland Technology Park and Oakland University made financial contributions to the project, and a total of five local, state, and federal funding sources were secured and commingled to make the DDI a reality.

Defining the relationship between infrastructure and community identity to send the right message.

Prior to the DDI, branding wasn’t allowed on Michigan bridges. But the city knew the DDI was something special, and wanted it to look the part. OHM Advisors responded with a bridge design with stunning visual impact. Then we took things a step further, spearheading discussions with MDOT and the FHWA about branding on state-owned assets. We introduced successful examples of branded infrastructure from around the country, and we successfully secured permission for another first-of-its-kind for the state: an impressively scaled and artistically lit Auburn Hills crest adorning the bridge. The effort has spurred MDOT to investigate a statewide policy on branding as a source of private funding for infrastructure.

Creating connectivity with pedestrian/bicycle facilities.

To further improve the bridge aesthetics and encourage foot and bike traffic into the university and business district, we added pedestrian/bicycle facilities across I-75, an element which didn’t previously exist. The pathway is located between the bridge lanes east and westbound and includes pedestrian crossings at signalized low speed ramps. Barrier walls separate the pathway from the traffic. This safe and welcoming addition helps make the project one of the most attractive interchange corridors in the state.

Enhancing University Drive.

Oakland University considers University Drive to be its mile-long driveway. As part of the interchange project, OHM Advisors took a holistic approach to create a streetscape that links the university with the city of Auburn Hills. The “driveway” continues the iconic and aesthetic features of the bridge and further encourages walking and biking in the community. An entry branding and wayfinding module just east of the interchange features granite blocks, landscaping, and a decorative sign that brands Auburn Hills as the gateway to Oakland University.

"We are very, very proud of this project. Having the first DDI in Auburn Hills is really just a fantastic thing for our community. We're getting a lot of calls from people who are driving through the area and just saying how beautiful it is."
Stephanie Carroll - Manager of Business Development, City of Auburn Hills, MI

Awards and Honors

Community

Advancing Communities

The DDI solved a complicated interchange problem, making it faster and safer to get to and from Auburn Hills’ university and business district. Not only did the innovative solution save considerable construction costs, motorists also save on fuel due to a smoother commute. The environment wins as well thanks to less greenhouse gas production and preservation of area wetlands.

City officials no longer worry about losing business due to poor infrastructure. In fact, current businesses are excited about the new interchange, and they appreciate that employees are getting to work on time thanks to fewer detours and delays on the road. What’s more, interest in the Oakland Technology Park area is on the rise, thanks in part to the investment in infrastructure and the branding that helps define the city as an innovation destination. More development will create additional jobs and stimulate further investment to benefit all members of the community.

 

Full Services Provided

  • Traffic analysis and modeling
  • Geometric concepts and design criteria
  • Geotechnical investigation
  • Maintenance of traffic concepts
  • Right-of-way coordination
  • Funding assistance
  • Exploration of enhancement opportunities
  • Construction estimating

 

Infrastructure Getting it Done.

The first interchange of its kind in Michigan.

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